His Butler, Flame
by KarotsaMused
Summary: AU to the tune of Kuroshitsuji/Black Butler. Ed is the young master, Mustang the demon. Set pre-series and in Youswell. Rating for language and loss of limbs.


A/N: In Honor Of The Not-Pocalypse, I post a Fullmetal AU set in the sort of plot contrivance culled from Black Butler.

In other words, as my Bean put it: Sebastia-stang. Please enjoy your daily single serving of pure crack. Big ups to the Bean for the beta.

* * *

><p>Mustang was still smiling as he bent to unlace his Young Master's boots.<p>

"If I may say so, sir, that was an inspired touch of subterfuge, making all of that gold. Why, some days I wonder whether you entered into our contract for fun."

Ed fisted his hands on the edge of the bed, though he smiled faintly. "Doing what you've implied is illegal. Did you _find_ anything?"

Mustang looked up through his bangs, gently setting Edward's boots aside. He sighed. "None whatsoever, Master. Youswell is full of miners, not alchemists. I could search much more quickly on my own if you'd only give the word-"

"And miss the moment when we find it? No. You'll tell me where it is, and _I_ will take the Stone."

Mustang lowered his head in a bow. "Of course, Master. As you say."

As Mustang's hands traveled up his leg, rolling down the heavy sock he used to protect the inside of his boot from his automail foot, Ed leaned back. He looked out the window over Mustang's shoulder and murmured, "I thought you didn't get impatient."

"Why, Master, I am nothing of the kind." Mustang folded the sock and moved to Ed's other foot, his gloves dry and cool. "Impatience is such a human trait. It is the duty of a good butler to anticipate his master's every need."

Ed grunted. "Don't talk like that around Al."

"As you wish," murmured Mustang, rising to his feet. He took Ed's glove off, finger by finger, careful with the automail where the fabric pulled.

"I mean it. I know you stay up with him." Ed narrowed his eyes.

Mustang hummed, "Of course. I serve the Elrics, and one of my masters has the unfortunate inability to sleep. A butler should soothe."

"Mustang-"

"And I expressly obey your order never to reveal what I am or what you've done." He met Ed's eyes with a brief, intense gaze.

Ed scowled and pulled his hand back. The sound of gears shifting accompanied his flexing his hand into a fist.

"I'll get the oil," said Mustang without missing a beat.

"Do you have to do this every time," breathed Ed, as Mustang moved around behind him and pulled the coat from his shoulders.

"I am protecting my interests as thoroughly as you protect yours, Master," purred Mustang. "I'll never forget what you told me."

Dryly, Ed said, "What part."

Mustang chuckled, lifting Ed's automail arm with no apparent effort, expertly applying oil. "That your service to the Fuhrer was an agreement of mutual self-interest. That you would submit to his wishes in whatever manner they were presented so long as your servitude assisted your own ends."

Ed tilted his head away and growled. "I'm not like you."

"Relax your hand, Master," murmured Mustang.

Ed curled it into a tighter fist for just a brief moment, then relaxed it. Already, begrudgingly, he had to admit to himself that Mustang's work was almost as good as Winry's. He could feel less pull when he moved, and his arm was nearly silent in its operation.

He gritted his teeth. "I'm not like you."

"Acknowledged, Master." Mustang took his time on each finger. "You have the blood of Hoenheim of the Light in your veins. We are not alike in the slightest."

"I _told_ you not to say his name!" snapped Ed.

As he leaned over his shoulder, Mustang met his eyes again, the blackness of the iris glinting red in the candlelight. "You're so tense, Master. The weight on your shoulders is absolutely horrible for your back."

Ed caught the metaphor and whipped around, feeling Mustang's cool breath against his cheek. He gritted his teeth. "I'll take care of myself tonight, Mustang. Go play cards with Al. That's an order."

Mustang's face almost looked kind when he smiled, from that close up. "As you wish, Master," he murmured, secreting the oil can away and bowing at the door.

* * *

><p>The first thing he remembered, after the flash of bright light, and the tearing hands, and Alphonse disintegrating before his eyes, the first thing he remembered was the sickening <em>plop<em> of the blood gushing from his thigh hitting the concrete floor.

He remembered it clearly, and from it the freezing cold and the pain that shot through him hard enough to paralyze, to make him gasp for breath.

And after the sound, he realized he was screaming.

Gasping for breath, he met the eyes of the _thing_ in the center of the transmutation circle and knew it wasn't his mother, the convulsing mass of organs with two eyes locked on him, and teeth, and tongue, the head incomplete and lolling. And how his blood, as it pooled on the ground and he couldn't make his shaking hands touch the circle again, ran down across the floor and toward the creature.

And how that tongue, long and red and violet, had reached for his blood, had tasted it, had drawn through it with a thick hunger that made the creature's eyes flutter.

Ed was aware of the knowledge that Al was close. That he had to grab him, to pull him back, but his blood was obscuring the array and now the creature they'd brought back - _not mom_ - was rolling over, growing muscle and skin and dark hair and was smiling.

Naked, it crouched on the floor, taking the shape of a man.

It said, "You can't die yet, not now."

"Al!" Ed cried, unable to articulate beyond his need.

"Oh? Alright. But I'll need a bit more power to get him back for you."

The man bent and took Ed's right wrist in a gentle grip, and with nothing more than a tug, severed his right arm from the shoulder.

It didn't hurt until Ed saw his arm dangling from the man's hand.

"I'll get his soul, but you're going to have to tie it down. Find something to draw with."

Ed remembered him laughing, and Al screaming, and a rough noise that must have been coming from him.

Ed remembered drawing the circle with his own blood, in a suit of armor propped up by a naked man who kept _smiling_ at him.

Ed remembered hating that smile, and passing out in a pair of strong, cold arms.

* * *

><p>Ed woke panting, his throat tight.<p>

"The same old nightmare, Master?" murmured Mustang, taking his hand back from Ed's shoulder.

Ed grimaced and sat up, shaking his hand away. "I told you to go play cards with Al."

"He kindly requested I retire, Master, out of deference to a perceived need for sleep." Mustang's smile was a pale crescent in the darkness. "When I checked in on my Master and found him in need, why, of course I rushed to his aid."

"I didn't need your help."

"I've brought some cold water, if my lord would care to have a drink."

Ed turned, frowning, but accepted the glass from Mustang's white-gloved hand. The water was indeed cold, cutting down his throat and settling the tightness in his gut. "What time is it."

"It's a few hours after midnight. Dawn is a while away, yet."

"Then go and take care of yourself, Mustang. I don't need you here."

Mustang smiled, bowing. "I exist only to serve my lord and his esteemed brother."

Ed grunted, the same old phrase rankling. For all appearances, Mustang _did_ only exist to serve. He never ate, never drank, never slept. He never asked for anything for himself, procuring clothing and supplies without apparent care and from no obvious providence. He only followed Ed like a shadow, doing as he bade, without complaint.

"Right. And you've searched the area for the Stone."

"Thrice, Master." Mustang wrinkled his nose. "The only thing I found was the faintest scent of Brigadier General Gran in the deposed Yoki's quarters. There appeared to be a memento of some sort that had rested on his windowsill."

Ed snorted. "That's fantastic. Just great."

"My sincerest apologies, Master. I did complete your report for General Hakuro."

"Let me see it," said Ed quickly. "You were too literal last time."

Mustang bowed, bringing the report over, and a candle. Ed scanned it. And winced. "Take out the part about the miners kicking me out. I don't blame them."

At Mustang's pause, Ed looked up. "Do it."

Mustang smiled as he bowed his head. "Of course, Master. My lord is a kind-hearted boy."

"Fuck off."

"As you wish."

* * *

><p>As he healed from the loss of his limbs, the days were sunny. Ed rested on a guest bed in the Rockbell house, looking out at the cloudless blue sky.<p>

And in the corner, wearing some of the late Mr. Rockbell's clothes, the creature sat, shaped like a man, and watched him.

In one of his more lucid moments, Ed asked, "What are you doing here?"

"Watching over you," said the man.

"Why?" asked Ed, looking over.

The man smiled. "It's my end of our deal, Master Edward."

Ed swallowed thickly. "I didn't make any deal with you."

"You did. You drew the circle, and summoned me, and sealed the summoning with your blood." He put his cheek on his fist, smiling without opening his mouth. "The circle you drew wasn't intended to do so, but you had been attempting the impossible. And your blood called to me instead."

"Impossible-?" asked Ed, latching onto the word that drove a knife through his heart.

The man's smile quirked. "The reason bringing back the dead is taboo isn't because it's morally bankrupt alone. The reason is that it's impossible. Once a soul is gone, it's gone. But the circle you drew created a vacuum to be filled." He gestured to himself. "And so, here I am."

Ed began to shake, every word deepening his grief. He gritted his teeth and looked away, determined not to cry.

"I never thought I would be called into servitude by the son of Hoenheim of the Light," murmured the man. "This is all so very curious."

"Don't say his name in front of me," hissed Ed, his voice unsteady.

"As you wish, Master."

Ed glared at him. "I'm not your-"

"But you are," said the man. "From the moment you gave me corporeal form, I was bound to you. And until your death, I will follow your every command."

Ed stared blankly.

"Are you wondering what I am?" the man asked. "Or are you wondering what happens once you die?"

"What about Al," said Ed, forcing a tongue like stone in his mouth to move. "His blood was in the transmutation too."

The man shrugged. "His body is no longer here, and his soul is bound down with _your_ blood, Master. It is the nature of the deal that he is off-limits. I am a somatic creature when I can be." His voice took on a hint of amusement. "I will perform what duties toward him you wish, but the orders must come from you."

Ed watched him, his eyes narrowed. "So what are you, then."

"Surely, your father being who he is, you would have some inkling."

"He left when I was little," growled Ed. He tried to sit up, but was too weak to maintain it.

The man's mouth quirked. "Little. I see. Well, then to put it succinctly, I am a demon. Your realm is quite different from the one I left, but your father's name is known there very well indeed."

Ed frowned. "Demons are imaginary and you're a liar."

In response, the man snapped his bare fingers and a small orange flame flickered from his fingertips. It hovered in the air, throwing off light but no soot, dancing over the man's skin. "I would never lie to my Master," murmured the demon.

Ed's jaw dropped. He shut his mouth. "That's a transmutation!"

The man paused. Then smiled. "I see we have much to teach each other, my lord."

* * *

><p>"Master? My lord, you must wake up or you'll miss your train."<p>

Ed's eyes fluttered open, and Mustang's face swam into focus. It was close, though the demon looked down at him with a bit of bland concern. "You've let your stomach air out again."

Ed sat up, and as the hem of his shirt slid down he let out a grunt. "Got hot."

"From what I've learned," said Mustang, effortlessly reaching in and helping Ed's shirt down the rest of the way, "that sort of behavior can make a human very fragile."

"Tell me something. Do you _try_ to be an asshole all the time?"

Mustang lifted Ed's automail hand and turned it over, feeling along the joints. "I don't know what you mean to imply. I have heard that prolonged nudity can cause humans to catch cold."

Ed bristled and took his hand back. "What time is it?"

Mustang held out his gloves, saying, "Nearly eight, my lord."

Ed grabbed his gloves, and jammed his fingers into them as Mustang sank to his knees. Ed scrambled to tie his hair back as Mustang slipped clean socks onto his feet, and brought his pants up to his thighs, the belt already fitted into the loops.

Mustang moved back enough for Ed to step into his boots and hitch his pants up. Ed shoved his arms into his coat as Mustang tied his laces. It was a pattern that had taken some time to develop, but Ed hadn't been able to get Mustang's hands off of him while he dressed. He'd insisted it wasn't proper for someone of Edward's station to be forced to dress himself.

He'd put his foot down on assistance with bathing.

Mustang rose to his feet again and smiled. "I do hope, for my lord's sake, that when we return to Central there will be some time for me to do the laundry."

"I'd have changed if you hadn't let me sleep in!" cried Ed, racing for the door.

Mustang carried his bag. "But you looked so tired, my lord. You said my name while you were sleeping again. I sat up beside you through the night."

Ed stopped with his hand on the knob, his shoulders tense.

"I come when my master calls," Mustang reminded him, before he could speak.

Ed looked over his shoulder and smiled thinly. "Then I shouldn't have named you, should I?"

Mustang smiled back. "Certainly not something so uncomplicated as 'Roy', my lord."

* * *

><p>The fittings for the automail left him shaking. Ed was weak, pain wracking his small body so that he couldn't sleep. He refused the drugs, he refused to scream, forcing his consciousness so he would <em>remember<em>. So he could atone somehow, for anchoring his brother to a heartless hunk of steel.

"I could assist you with that, Master," said the man in the corner of his bedroom. He hadn't left his seat, not once, watching Ed with dark eyes.

"Leave me alone," gritted Ed, though his words shook.

The man sighed. "My lord, I could not even if you ordered me to do so. Let me take your pain."

"_No_!" Ed hissed as his shoulder, jarred by his speech, sent new waves of pain rocketing over his chest.

"Then let me serve you. There are many functions I can perform, my young Master."

Ed closed his eyes tightly. "You couldn't get his body back."

The man shrugged. "No, but there is something that can. And I can help you find it."

"The—The Philosopher's Stone?"

Suddenly the man leaned over the bed, speaking almost in Ed's ear. "Of course you know it. The stone that allows its wielder to ignore the laws of equivalent exchange. I know its scent, my lord. I know its taste. I will find it for you, if you command me to."

Ed shivered at the cold breath down his neck. "A-and keep it for yourself?"

"No, master. I would find it for the sheer pleasure of obeying your command. I need nothing more than to serve the call of my lord's blood." The man smiled, baring white teeth in two perfect rows.

"Wh-what do I call you?" breathed Ed.

"I have no name, other than that which my master desires to call me."

Ed shuddered, his teeth clenching against a groan. "Are you suh-some k-ind of pervert?"

"Not at all, my lord. I am, and always will be, your most loyal and obedient servant."

* * *

><p>"Mister Mustang?"<p>

"Yes, Alphonse?"

"Are you writing my brother's official report again?"

Mustang looked up and smiled across the train seat at Alphonse. "Well, he's hardly in any position to do so, and it will be due all the same."

Al looked over at his brother, sleeping with his face pressed against his fist, and sighed. "It feels a little disingenuous."

"My dear Alphonse. I was there, the same as you. Edward has made it clear exactly how the report ought to portray his actions, and I've become a very good fabricator of his handwriting over these few years."

Al huffed a little. "Okay, but. Don't let him take advantage of you."

Mustang smiled then, slow and broad. "It's very kind of you to say so, but you have absolutely nothing to worry about."


End file.
